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101.
苏守坤 《沈阳农业大学学报》1998,29(3):256-258
利用水力旋流器,对水力机械的润滑、轴封用水进行净化,降低泥沙含量,使之达到技术供水标准。本文研究和分析了水力旋流器的结构、各部构件尺寸与净化泥沙性能的关系;指明了水经过旋流器的压力降的确定,使之既满足泥沙沉降的要求,又要保证供水系统的所需的压力值。 相似文献
102.
在非定点使用标准表的标准装置中,进行累积流量的测量时要用到流量计的仪表系数。通过实例计算介绍了另一种求得仪表系数的方法,即回归分析法。利用这种方法求得的流量计的仪表系数,由于减少了人为的误差,因此,大大提高了计算整个累积流量测量过程总液量的准确度,同时提高了工作效率。 相似文献
103.
体积管是检定流量计的标准器。YTG型双向体积管,其外型尺寸、主体结构、检定速度、日常管理等方面,均比单向体积管有明显的优点,并具有独特的容积补偿性,给体积管的管理、使用带来极大方便。介绍了YTG型双向体积管的结构、技术指标及其优越性,并建议在条件允许的情况下,尽可能使用双向体积管。 相似文献
104.
为研究双向流道灌水器水力性能,将其结构单元作为研究对象,以分叉角和回转半径两个结构参数为影响因素,采用正交试验设计16种结构参数组合方案,利用计算流体动力学软件Ansysfluent对流道内部流体的流动状态进行数值模拟,通过量纲分析建立流道结构参数与流道单元局部水头损失的回归模型。结果表明:双向流道单元局部水头损失与分叉角、回转半径和流道流速有关,分叉角与局部水头损失呈负相关关系,回转半径和速度与局部水头损失呈正相关关系;当入口流速为固定值时,分叉角为32.4°、回转半径为1.72 mm,流道单元局部水头损失最大;当设置10个流道单元时,交叉排列方式组合的灌水器流态指数较优。 相似文献
105.
R M McDowall 《Fish and Fisheries》2001,2(3):278-285
106.
为研究矿粒粒径对深海采矿扬矿泵过流部件磨损特性的影响,采用DPM模型模拟泵内固液两相流动,并以基于流体动力学的Oka磨损模型仿真颗粒对过流部件的磨损,分析扬矿泵在不同矿粒粒径下的磨损规律.研究结果表明:随着矿粒粒径的增大,首级叶轮及次级叶轮的前后盖板磨损量分布逐渐均匀,前盖板磨损量的集中区域从出口压力面向叶轮中部及进口吸力面转移,后盖板磨损量集中分布区域从进口吸力面一侧向出口压力面一侧转移,叶片进口和出口的磨损面积均逐渐增大;首级空间导叶及次级空间导叶的叶片背面进口磨损面积逐渐增大,在轮毂出口处磨损区域向外逐渐偏移,且该位置磨损面积逐渐减小;当矿粒粒径从1.0 mm增大到5.0 mm时,首级叶轮和次级叶轮的前盖板最大磨损量分别上升132.9%和104.2%,首级叶轮和次级叶轮的叶片最大磨损量分别上升172.3%和142.5%,首级叶轮和次级叶轮的后盖板最大磨损量分别上升251.4%和102.3%,首级导叶和次级导叶的最大磨损量分别下降87.08%和74.26%. 相似文献
107.
The purpose of this study is to simulate urban micro-climate change due to the variation of wind flow and temperature assuming situations before and after applying programs using urban infrastructure regeneration technologies (UIRTs), and to then quantitatively estimate effectiveness on the urban regeneration schems. UIRTs focus on improving the recycling efficiencies of reclaimed water and biogas produced and to enforce the linkage among all environmental infrastructures associated with water, waste, and energy in an urban block. To implement the micro-climate analyses, data such as land use, topography, building height and materials, and weather conditions were collected, and the results estimated based on fluid simulations of cold wind and temperature variation pathways. There were three programs used in the urban regeneration project in J city: river restoration, traditional market revitalization, and a primary school eco-school. The height of cold wind from the ground level was significantly elevated, and the maximum wind velocity differential between before and after increased by 0.12 m/s due to the expansion of the waterfront space and grassland through the three programs. Overall, a temperature at the ground level dropped by 1.6 °C. Based on these results, the three programs improved the urban environment at ground level, and might ultimately be capable of diminishing the urban heat island effect and mitigating the energy consumption of urban areas. 相似文献
108.
In this paper, partial differential equations of vortex flow-stream function in boundary fitted coordinates and related ADI equations were listed. The flow around a cylinder in quadrilateral area by auto control boundary was computed. The diagram of distribution of speed arrow, constant lines of flow-stream function, vortex, two speed parts and pressure were studied. 相似文献
109.
Comparison of nuclear DNA content of citrus rootstock populations by flow cytometry analysis 总被引:2,自引:0,他引:2
Citrus species are widely grown in the world. Plant characteristics of the rootstock populations used for orange, lemon, mandarin and grapefruit cultivars should be known as well as those of the cultivars that help true‐to‐type nursery plant production. In this study, cell nuclei were isolated from leaf tissues of seedlings of trifoliate orange, sour orange, rough lemon,‘Volkamer’ lemon,‘Cleopatra’ mandarin,‘Hyokan’, ‘Sanbokan’, ‘Kinkoje’, ‘Carrizo’ citrange and ‘Swingle’ citrumelo, and then fluorescence intensities were measured on propidium iodide‐stained nuclei by flow cytometry. Nuclei isolated from the triploid ‘Tahiti’ lime with a known nuclear genome size were used as the internal standard to estimate the nuclear DNA content of Citrus seedling populations in absolute units. Results obtained from cytograms and histograms indicated that all seedlings analyzed were diploid. In addition, differences between the species for nuclear DNA content were also found to be significant. ‘Hyokan’ seedlings had the biggest genome size, 0.984 pg/2C, whereas trifoliate orange seedlings had the smallest genome size, 0.678 pg/2C. Flow cytometry analysis could be used for obtaining accurate and rapid results for cytological observations of seedling populations of Citrus. 相似文献
110.